Abbott Handerson Thayer (August 12, 1849 - May 29, 1921) was an American artist, naturalist and teacher. As a painter of portraits, figures, animals and landscapes, he enjoyed a certain fame during his lifetime, as indicated by the fact that his paintings are part of the most important U.S. art collections. During the last third of his life, he worked together with his son, Gerald Handerson Thayer, on a major book about protective coloration in nature, titled Concealing Coloration in the Animal Kingdom: An Exposition of the Laws of Disguise Through Color and Pattern; Being a Summary of Abbott H. Thayerâ€™s Disclosures. First published by Macmillan in 1909, then reissued in 1918, it had an effect on the use of military camouflage during World War I. He also influenced American art by his efforts as a teacher who trained apprentices in his New Hampshire studio.